Generally, slide fasteners are widely used in garments and bags. The slide fasteners are constituted such that a plurality of unit meshing teeth are attached on a pair of supporting tapes in the lengthwise direction so as to be coupled or separated by a slider. Accordingly, the slide fasteners are used for opening or closing the products such as garments and bags.
In these slide fasteners, the supporting tapes are usually made of a fabric, and the unit meshing teeth and the slider are made of a synthetic resin or a metal. Further, the unit meshing teeth, the slider and the supporting tapes have a single pattern and a single color, and the pattern of them are significantly different from that of the garment, with the result that a pattern discontinuity is formed.
Accordingly, the slide fasteners cannot be harmonized with the garments, the bags and the personal articles, and therefore, the equilibrium is failed in the design. Therefore, diversified and colorful fashions cannot be realized, and the individuality is lost, while the design impression is damaged. Further, the liberty degree of the design is restricted.
In an attempt to solve the problems of the single color slide fasteners, UK Patent Application GB 2 177 967 A, Japanese Patent Publication No. Sho-61-293822 and Korean Patent Publication No. 1990-0001907 (all the same invention respectively filed to United Kingdom, Japan and Korea, which are to be called “cited invention” below) disclose a new method for manufacturing a slide fastener stringer.
In this method for manufacturing the slide fastener stringer, a stringer tape is involved, and there are also formed multi-color injection-molded element trains that are attached on the stringer tape in the longitudinal direction. This method includes the steps of: (a) injection-molding a plurality of longitudinally separated coupling element trains on a stringer tape in the longitudinal direction, the injection-molded coupling element trains having a first color and being separated from each other by non-element portions; (b) injection-molding a plurality of longitudinally separated coupling element trains on a stringer tape along the non-element portions, these newly injection-molded coupling element trains having a second color different from the first color of the previously injection-molded coupling element trains; and (c) repeatedly carrying out the step (b) until the non-element portions are filled with the injection-molded coupling elements.
In connection with the above described manufacturing method, an individual slide fastener, i.e., a commodity slide fastener which can be used in an adult garment or the like will be criticized.
For example, a slide fastener will be examined in which the total length is 500 mm, the pitch of the elements is 2 mm, and the number of the elements is 250.
At a first process, five elements are injection-molded with a certain color, then the injection-molded elements are cooled, and then the stringer tape is fed further. At a second process, another five elements are injection-molded with another color, then the injection-molded elements are cooled, and then the stringer tape is fed still further. These processes are repeated 50 times to manufactured one slide fastener.
Accordingly, there are serious problems in this method. That is, in order to manufacture one single slide fastener, the process of injection-molding, cooling and feeding has to be carried out 50 times. During the cooling, there are accompanied contractions and deformations, while during the feeding, the dislocation errors are increased. As a result, the pitch distance cannot be uniform between the element groups that have been injection-molded at different stages.
Thus in the above described method, in manufacturing a single slide fastener, the process of injection-molding, cooling and feeding has to be carried out several-score times repeatedly. Thus the thermal contractions and dislocations occur several-score times, and therefore, the pitches of the unit meshing teeth cannot be uniform.
Further, the gaps between the teeth over the different processes are not constant, and therefore, a practically useful fastener cannot be realized.
So, in order to solve the problem, the Applicant invented a “Multi Color Slide Fastener Manufacturing Apparatus” and filed it as a Korean Patent Application No. 2001-021368. The invention is constituted of a molding die consisting of upper and lower dies, a plurality of unit meshing teeth forming slots being formed in a longitudinal direction thereof, a plurality of molding material injecting passages being mutually isolatedly formed to inject the molding materials of different colors into respective groups of the meshing teeth forming slots and a plurality of sprue holes being formed for injecting the molding materials of different colors into the respective molding material injecting passages; a cylinder block coupled to a top of the molding die, and consisting of a plurality of vertical cylinders and a plurality of horizontal cylinders in a crossing form, a plurality of discharge holes being formed correspondingly with the sprue holes of the upper die to communicate to the horizontal cylinders; a heating means for heating the cylinder block; a plurality of carrying screws respectively inserted into the vertical cylinders to carry the molding materials of different colors; a driving means for driving the carrying screws; a plurality of pistons respectively inserted into the horizontal cylinders, for extruding the molding materials; another driving means for driving the piston; and an opening/closing means for intermittently opening-closing the respective discharge holes of the cylinder block to intermittently inject the molding materials of different colors.
According to the invention as described above, the multi-color slide fasteners can be continuously produced by injecting the molding materials of different colors into the meshing teeth forming slots of the molding die by one shot. That is, a plurality of groups of the meshing teeth are formed with different colors by one shot, so that the meshing teeth could form various patterns.
That is, one whole multi-color slide fastener can be manufactured by one shot, and therefore, the pitches and gaps between the unit meshing teeth are uniform. Accordingly, not only the multi-color slide fasteners can be mass-produced, but also their quality and reliability can be upgraded. Further, various patterns and colors can be formed on the slide fastener. Thus the multi-color slide fastener manufacturing apparatus is capable of manufacturing the multi-color slide fastener in a practical and satisfactory manner. Its production is not only fast but also its pitches are uniform, while the product defects are eliminated.
However, in the apparatus of the above mentioned prior art, there are the following problems. That is, screws and pistons are coupled to a plurality of vertical and horizontal cylinders which are disposed in directions crossing a cylinder block, thereby carrying the molding materials. Accordingly, the molding materials (synthetic resins) cannot be efficiently carried from the horizontal cylinders to the sprue holes of the molding die.
Further, gears are interlocked to a plurality of carrying screws, and therefore, when the plurality of the intermeshed gears revolve, there is formed a high load. Consequently, not only the gears cannot smoothly revolve, but also the life expectancies of the carrying screws are shortened.
Further, there are a plurality of cylinder blocks, and there is installed a valve in each of the plurality of the passages. Thus the constitution is complicated, and disorders are frequent. Further, if the apparatus is used for a long time, the valves are subjected to malfunctions, and therefore, the final products become irregular, thereby losing the product reliability.